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Research was conducted to develop a computer model to solve the governing equations of fluid mechanics for the time dependent air flow around a worker immersed in a uniform free stream. The essential feature of the model was the ability to capture the formation and evolution of the near wake, reverse flow zone, and thus to permit the industrial hygiene engineer to examine the influence of changing the direction of air flow, worker position, and air speed on the position and size of this zone. The model, as developed, required substantial computer resources to examine the vortex shedding phenomenon. Modifications to improve speed and accuracy were noted to be under evaluation. This discrete vortex method was employed in this model. The method was able to simulate effectively the time dependent flow phenomenon of vortex shedding past an elliptical cylinder. This simulation was a valuable tool in understanding how the recirculation zone forms and changes periodically in time. This two dimensional approach yielded estimates of concentration that were in reasonable agreement with measured values, although further validation and study are needed to refine and improve the model. The discrete vortex method had an important advantage over finite difference and finite element approaches in that it avoided the problem of numerical viscosity associated with small grid sizes.